Optimization of Almond Kernels Drying under Infrared-vacuum Condition with Microwave Pretreatment using Response Surface Method and Genetic Algorithm

The aim of this study was optimization of almond kernels drying with infrared-vacuum dryer and microwave pretreatment using Response Surface Methodology (RSM) and Genetic Algorithm (GA). The almond kernels were dried as thin layer with air temperatures of 30, 45 and 75°C vacuum pressures of 20, 40 and 60 kPa and microwave powers of 270, 450, and 630W. Design expert software was used to generate the experimental designs, statistical analysis, and regression models. The results showed that the optimum point for drying of almond kernels under infrared-vacuum dryer and microwave pretreatment with RSM method and considering the minimum value of shrinkage, energy consumption, and total color change as well as the maximum value of effective moisture diffusivity can be achieved at air temperature of 45°C, vacuum pressure of 34.04 kPa, and microwave power of 270W with 68% desirability and optimum point with GA method can be obtained at air temperature of 45°C, vacuum pressure of 34.05 kPa and microwave power of 270W.